RADIOWORLD ENGINEERING EXTRA
Pragmatics 101: The Big Picture of the Small End of Power Generation
Time to consider practical aspects to enhance safety and performance
June 13, 2018
A good friend, for whom pragmatism is one of his greatest assets, calls these select items …
THE RACK OF LAST RESORT
One of my most learned mentors had a great adage: Any item in the mainstream of your business is critical and worthy of your complete attention. Our fictitious little power plant, critical at this moment, started on the first attempt because all the little details had been addressed. Periodic maintenance is absolutely necessary such as the exercise routine mentioned above. Proper fuel storage might be evaluated as the second most important focus. As the vast majority of these small portable units run on gasoline, remember that unpressurized gasoline evaporates, leaving a residue of caulk-like material similar in many ways to turpentine. As a bonus, periodic exercise burns off some of the onboard fuel, precipitating replacement of fuel over
Never fuel the generator while it is running or in a highly heated condition!
A typical portable, light-duty generator that might be used as “old reliable” in our dark and stormy night scenario. BY CHARLES S. “BUC” FITCH, P.E.
In the first and second parts of this series, we outlined the scope of small power generators, how they do what they do, general factors (plus and minus) that affect their performance, and the criteria for sizing and optimal type. In this installment, we’ll begin to annotate the litany of practical items that should enhance safety, performance, reliability and overall satisfaction.
IT WAS A DARK AND STORMY NIGHT
So, darkness has come. The storm, the flood, the winds, the unpaid electric bill (just kidding about the bill) … the foreseen but unwelcome calamity has now arrived, and commercial power has been lost at your station. When the moment is safe, you glance
outside and know that this is worse than you thought, as it is totally dark from horizon to horizon. In the relative blaze of the building emergency lights, you locate your trusty flashlight and headlamp in their trickle chargers. You unlock the fireproof storage shed behind the studio and roll out “old reliable” to the pre-prepared operating location. You’re of the mind that there is no such thing as too much ground, so you connect up the generator frame ground cable to the rod you’ve hammered in. Next comes the SJO power cable that you’ve stored in a convenient warm place so this important connection is flexible and supple enough to roll out flat and straight. This main umbilical of life for your station is ultra-bright yellow or orange (or both) so that no one will trip or
(hopefully) drive over it. A few big traffic cones are additional safety markers and make you and your generator look dramatic and important! All plugs and receptacles are twistlock type, so everything goes together quickly and accurately. Since you exercise the generator for at least 20 minutes every month and under load every six months, this mighty-mini starts in just a few seconds. Within the minute it takes to walk inside, the generator is ready to take a load. You throw the switch on the manual transfer switch, and voilà — your station has come back to life, albeit in an abbreviated form. As we noted in the last episode, prudent selection of gear and features should allow your station to provide near continuous, meaningful service to your community.
time. But more aggressive fuel discipline is needed, such as a fuel stabilizer additive. Usually the engine manufacturer will provide selection guidance in the instruction manual, sometimes as specific as their approved and tested additive choices. “Stale” fuel is deleterious to small engines for a great number of reasons, including hard starting, residual material in the fuel system components such as the carburetor, low engine power output, etc. Also keep in mind that gasoline and most liquid petroleum products have solvent properties and will dissolve paint, more solid oils, wood products and the like. These alien materials will travel along with the gas in a suspended state, landing wherever they want. Clean, fresh gas is essential. Do not forget to treat any additional fuel stored on site in a similar manner (extra five-gallon cans or tanks perhaps), and check this backup fuel whenever you exercise the generator. Gasoline and most volatile gases are explosive in nature and demand special, attentive handling. For this reason, never fuel the generator while it is running or in a highly heated condition! (continued on page 22)
Radio World Engineering Extra 249 - June 13, 2018 issue